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PDR
1345632.  Thu Apr 09, 2020 4:53 pm Reply with quote

suze wrote:
Coming back to the actual topic of the thread,


Aw, Miiiiss - our normal teacher lets us do it <pout>


Quote:
let us suppose that we are indeed designing the next Milton Keynes. Should we, or should we not, build into it features that are only necessary if we suppose that one or more pandemic incidents will occur?


Actually we don't need to just think of pandemics. High-density living usually has an associated increased risk of spreading all sorts of microbial, bacterial and viral conditions. Especially if there is any element of common ventilation (air conditioning or heating) or water supply - the classic large resort hotel creates a huge risk of legionnaire's disease if it gets into either the air-conditioning water (or the hot water system if people shower rather than bathe). High density living does the exact opposite of social distancing and so increases the risk of onward transmission and the exponential co-efficient of the transmission rate (the closer people live together the steeper the curve).

Quote:

Similarly, in the south of England we build on the assumption that it hardly ever snows (and this has been a snow free winter in the south of England, although the first one for a decade). In Maine and Switzerland they really don't.


We had a brief snowfall here in surrey at about 4AM a week or two ago, actually!

Quote:
When we design our cities at present, do we consider the possibility of a pandemic event? If we do not, will we now start to?


But we're supposed ti build for 125-year events, so I don't see why we SHOULDN'T be taking cross-infection risks into account.

I would.

PDR

 
barbados
1345633.  Thu Apr 09, 2020 5:12 pm Reply with quote

Quote:
We had a brief snowfall here in surrey at about 4AM a week or two ago, actually!

There was also snowfall in a certain medway town beginning with C

 
PDR
1345635.  Thu Apr 09, 2020 5:49 pm Reply with quote

Seaford?

PDR

 
suze
1345637.  Thu Apr 09, 2020 6:12 pm Reply with quote

Was there? Chatham is 200 feet or so higher than we are in Rochester so I'm not especially surprised, but I'm fairly sure that I have not seen a snowflake this winter. Mind you, in the south east a White Easter is actually more common than a White Christmas, so come back to me next week.


PDR wrote:
But we're supposed ti build for 125-year events, so I don't see why we SHOULDN'T be taking cross-infection risks into account.


See, this is the bit that I'm not entirely sure about.

Whenever it snows in the south of England, it becames clear that our railways (and to a lesser extent our roads) are indeed built on the "It hardly ever snows here" principle. While it doesn't snow much in the south of England, the average must be something like three days per year - and yet it seems to be accepted that it's not reasonable to expect the railways to be able to deal with it.

So we are asked to believe that a 125 day event need not be considered. The good folks of countries like Russia and Switzerland find this rather amusing.

Pandemics are fortunately less common than snow. What have we had in recorded British history of the same magnitude as the current event? The Black Death in 1349, the Great Plague of 1665, the Spanish Flu in 1919 (against which no lockdown-type measures were imposed in Britain, although they were in the US), is that about it? So four events in ~700 years makes it a 175 year event.

Should we be building for that? This is a genuine question, and I don't know the answer.

 
barbados
1345638.  Thu Apr 09, 2020 7:42 pm Reply with quote

The answer really is no.
175, is approximately 2.5 lifespans and while we are pretty well known for building things that last, there isnít really much that is that old, sure weíve got the Queen, and she has some properties that are almost as old as she is, but most stuff isnít that old.

On a point of pedantry, you seem to have overlooked the biggest pandemic of all HIV and while there are fluctuating numbers, it is still an ongoing pandemic as it has been for nigh on 40 years.

 
PDR
1345644.  Fri Apr 10, 2020 3:23 am Reply with quote

suze wrote:

See, this is the bit that I'm not entirely sure about.

Whenever it snows in the south of England, it becames clear that our railways (and to a lesser extent our roads) are indeed built on the "It hardly ever snows here" principle. While it doesn't snow much in the south of England, the average must be something like three days per year - and yet it seems to be accepted that it's not reasonable to expect the railways to be able to deal with it.

So we are asked to believe that a 125 day event need not be considered. The good folks of countries like Russia and Switzerland find this rather amusing.


Risk management considers probability of occurrence, but it also considers the consequence of occurrence and the cost of mitigation (per unit reduction in probability and consequence, if you have a good system). A day or two of snow may happen every year, but the cost of any significant mitigation is typically much greater then the cost of the disruption, so it doesn't make sense to provision Russian or Swedish-style snow-capable railways. But even in the UK we design covered sports stadia to a design case which has (IIRC) 300mm of settled snow on the roof, because even though this may only happen once every hundred years the consequence of a roof falling onto a stadium full of people is considered unacceptable (even if they're only football fans).

But the consequence of pandemics can be huge. Even if we ignore the loss of life (to avoid getting into a debate about the safety-analysis/insurance-industry rule-of-thumb that each life is scored as a $1m loss) the pure economic consequence of what we're doing now will be somewhere around five to ten worst-case HS2s (my guess - other guesses are available) and we will be paying off the bill for at least a generation. Anything we do in mitigation that reduces the extent or sensitivity of the pandemic has a potentially huge mitigation effect on that number - the whole "fallen the curve" thing isn't really about saving lives - it's about reducing the disruption effect of higher proportions of the population being infected simultaneously.

Barbados mentions the HIV pandemic - the cost of this has become pretty negligible because quite early on we mitigated it through a wholesale switch to barrier methods of contraception for "casual relationships". That flattened the curve, and then we introduced other behavioural changes for those who were infected. The final arrival of effective *treatments* has really only improved the survival rate - it did nothing for the infection rate. But the cost of mitigation (condoms, safe sex etc) was small compared to the cost of the consequence so of course it was adopted.

I haven't seen any epidemiological studies yet, but I would suspect that the high-density living is one of the reasons why there have been "steep curves" in some Italian cities and places like New York. We don't have that kind of living density (with a few small-scale exceptions), but I suspect (my guess, other guesses are available) that we would be suffering a much more severe burden if we did.

So in summary I would suggest it's the relationship between cost of consequence and cost of mitigation (per unit consequence reduction) that is the issue, not just the cost of mitigation.

PDR

 
barbados
1345645.  Fri Apr 10, 2020 4:06 am Reply with quote

The problem, as I see it, with the mitigation process above, is the costly pandemics tend to have airborne causes. This would mean that we would need not to adjust the environment we live in, we would need to evolve into a non social species. It is the meeting of people that has spread all of the illness in the world, and unless we stop that there is little point in changing our urban environment. As long as we build the infrastructure to cope with it, there is nothing wrong with mass conurbations. What would be wrong would be to build a Milton Keynes and only provide it with a cottage hospital for example.

 
cnb
1345655.  Fri Apr 10, 2020 6:41 am Reply with quote

suze wrote:
Whenever it snows in the south of England, it becames clear that our railways (and to a lesser extent our roads) are indeed built on the "It hardly ever snows here" principle. While it doesn't snow much in the south of England, the average must be something like three days per year - and yet it seems to be accepted that it's not reasonable to expect the railways to be able to deal with it.

So we are asked to believe that a 125 day event need not be considered.

It's not only the frequency of the event that matters, it's the impact that event has when it occurs.
If the railways operate at 50% capacity for a day, the impact is small. Perhaps 2% of commuters won't be able to go to work that day, but many of them will be able to do some work from home. The event is normally over in a day or two, so some of the missed work will be made up over following days. The economic impact is probably less than 1% of that day's GDP. With three snow days per year, that's one hundredth of one percent of GDP. £22 million per year across the country doesn't get you very much railway engineering, so it's not worth doing anything about the reduced capacity on those snow days.

 
Celebaelin
1345663.  Fri Apr 10, 2020 7:39 am Reply with quote

Treading on suze's turf a bit here but a Polish guy I used to work with used to laugh his head off when a couple of centimetres of snow made everyone go crazy ape. Apparently in Poland they only have that reaction/excuse on '-40 days'.

 
suze
1345665.  Fri Apr 10, 2020 7:53 am Reply with quote

Are you sure he wasn't a Russian? -40 has only been recorded twice in the history of Poland, and both observations are considered doubtful. But yes, you're basically right - almost everyone outside Britain thinks that we're comically rubbish at dealing with snow.


cnb wrote:
With three snow days per year, that's one hundredth of one percent of GDP. £22 million per year across the country doesn't get you very much railway engineering, so it's not worth doing anything about the reduced capacity on those snow days.


But if railways were a new thing, and it were only now that we were building railways at the rate that they did in the 1840s, would we think differently about it?


barbados wrote:
On a point of pedantry, you seem to have overlooked the biggest pandemic of all HIV and while there are fluctuating numbers, it is still an ongoing pandemic as it has been for nigh on 40 years.


You're absolutely right of course, but the reason I ignored it is that - in the developed world at least - it's really extremely difficult to catch HIV "by accident". It is theoretically possible to catch HIV by being sneezed on by a person who has it, or by handling the bag of frozen peas which a person who has it has handled, but it would require an extraordinary coincidence of a number of rare circumstances and the epidemiologists don't even consider the possibility when they construct their models.

 
barbados
1345666.  Fri Apr 10, 2020 8:58 am Reply with quote

It would appear there has been modelling done to estimate the effect of a pandemic on the economy.
https://www.who.int/bulletin/volumes/96/2/17-199588/en/
I have no idea what all of that means, but I think it suggests that the average in a low probability / high effect influenza pandemic is a cost of around 0.6% of GNI (lower in high income countries, higher in lower income)
But in order to counter the effect of these low probability / high impact pandemics are we need to to isolate, because the high impact comes about when the cause is something that is mandated for doesn't occur.
Every year there is an influenza "season" we counter that by estimating what strain is going to be virilant that year, then vaccinating against that particular strain. The problem occurs when we have a strain that comes out of left field. If I understand the figures correctly, the last flu season (2018/19) saw us with 1692 deaths ( https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/839350/Surveillance_of_influenza_and_other_respiratory_viruses_in_the_UK_2018_to_2019-FINAL.pdf ). Against 26,408 the year before so we would have got the guess pretty much spot on, unless there is another more logical reason for the difference in figures. The likelihood of being able to preempt the current pandemic must be vanishingly small. Can we protect against every possible outcome without confining ourselves to our homes and not socialising in anyway - and is that a desired lifestyle bearing in mind this is the first time we have had to encounter such measures?

 
cnb
1345706.  Fri Apr 10, 2020 3:58 pm Reply with quote

suze wrote:
But if railways were a new thing, and it were only now that we were building railways at the rate that they did in the 1840s, would we think differently about it?


I doubt we'd do anything specifically to avoid problems caused by snow, but there are things we'd do differently for other reasons that would reduce the impact of snowfall. We wouldn't use third rail power supplies, we wouldn't have bits of century-old signalling technology still around, and we'd be designing the routes so that there were no level crossings. All of those changes would increase the number of trains we could run in snowy conditions.

 
cnb
1345708.  Fri Apr 10, 2020 4:13 pm Reply with quote

barbados wrote:
As far as Corona pandemics, there have been 3, SARS, MERS, and now Covid.

Five, I think. Coronaviruses 229E and OC43 (the 'common cold' viruses) are both pandemic, but they kill very few people.

 
barbados
1345715.  Fri Apr 10, 2020 6:14 pm Reply with quote

Iím not sure, are the corona strains of the common cold (around 10-15%) truly pandemic?
I canít recall there being a cold epidemic anywhere in my lifetime

 
suze
1345718.  Fri Apr 10, 2020 7:04 pm Reply with quote

They don't normally get spoken about as "epidemics", since the common cold is rarely serious. Not many people die of a cold, and most people who have one go about their business much as usual.

But one definition of "epidemic" is that if 15 people per 100,000 catch the disease two weeks running, then it is an epidemic. (That definition is in fact the one used for bacterial meningitis.)

100,000 is the population of a town like Crawley or Woking - and certainly in winter, you'd expect many more people than 15 to catch a cold each week.

A disease doesn't even have to be contagious to be epidemic. About one quarter of people in the UK suffer from hay fever to a greater or lesser extent, me among them. It's not contagious, but it's one of the most common diseases of the lot - and it's rarely spoken about as a cause for major alarm.

Incidentally, right now there probably needs to be some public information about hay fever, because the symptoms are quite similar to those of the other thing that's going around. Hay fever doesn't usually cause an elevated temperature, the coronavirus rarely causes a blocked nose. But it's not quite as simple as that, so there is a risk of false positive (and indeed false negative) self diagnoses.

 

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